The described invention relates in general to sharpening devices and the like, and more specifically to a pencil sharpener that includes a self-cleaning mechanism for automatically removing debris from the gear set that forms a portion of the cutting mechanism of the pencil sharpener.
This invention relates to the fixed internal gear that drives the helical cutter in manual and electric pencil sharpeners by way of the cutter gear, which is attached to one end of the cutter. Because this gear set is most conveniently located adjacent to the pencil cutting area and in the same compartment with the pencil shavings receptacle, it is exposed to wood shavings and ground pencil core debris (“foreign material”). When this debris enters the gear set, it is often pressed into the troughs of the internal gear. If allowed to accumulate, this material can begin to physically obstruct the cutter gear teeth entering into the internal gear teeth, eventually jamming the gear set and preventing further sharpening.
Conventional techniques for addressing this problem include covering the internal gear or adding additional clearance to the gear set. Covers, typically attached to the rotating carrier, are designed to prevent pencil shavings from entering the gear set. These covers are somewhat effective, but it is difficult to completely seal the gear set without increasing the cost or complicating the assembly. Additional clearance has been added to the gears by increasing backlash or reducing (since one of the gears is an internal gear) the center-to-center distance, but this too is only marginally effective. Thus, there is an ongoing need for pencil sharpener that includes a self-cleaning mechanism for automatically removing foreign material from the gears involved in sharpening.